Question

Please help me with this!My English teacher waiting for me to do that , but I don't get it .

Answer 1

This is a pun because the caption says "The streets were awfully deserted last night" which is "funny" because desserts are standing in the streets. 

Answer 2

"Deserted" relates to "empty", while "dessert" relates to a sweet post dinner treat. So, in the statement, one would assume that deserted related to an empty street, when in fact it related to Dessert-ed meaningful of desserts, which is the play on words.